The present invention is directed to dental equipment having means for delivering energy to a dental handpiece that contains a tool. The tool can be subjected to ultrasound oscillations by a resonator arranged in the handpiece. Also, energy can be delivered to a dental handpiece that contains a surgical tool using radio-frequency current. A transmission cable is connected, first, to a supply part and, second to the handpiece. The transmission cable contains an inner conductor and a shielded line arranged coaxially thereto.
Radio frequency (RF) surgery handpieces as well as ultrasound handpieces are both known in dental medicine. Whereas ultrasound handpieces are usually used for removing deposits at the teeth, particularly for removing dental tartar, RF surgery handpieces are utilized for cutting and coagulating gingiva. Both piezo-ceramic transducers (as disclosed in U.S. Pat. No. 3,809,977) as well as magnetostrictive transducers (as disclosed in U.S. Pat. Nos. 3,076,904, and 3,930,173) are used for the excitation of the tool tip in ultrasound handpieces. The supply is located externally of the handpiece in both applications. The same is also true of RF surgery handpieces (apparatus bearing the designation "SIROTOM" of Siemens AG). Whereas the transducer for an ultrasound handpiece for removing dental tartar is operated with a frequency of about 30 kHz, i.e., in the lower RF region, surgical handpieces are operated with a frequency of about 2 MHz.
An object of the present invention in both types of handpiece is to be able to provide an illumination and/or display lamp that is usually operated with DC voltage or with a low frequency alternating voltage of about 50 through 100 Hz in a simple way without having disturbances arise in the transmission of the RF energy.
If the energy transmission for both energy forms were provided in the traditional way, i.e., with the assistance of a cable having immediately neighboring, parallel lines, then considerable disturbances or, respectively, mutual influencings would occur. Thus, sufficient RF power would flow to the lamp and would effect the lamps brightness dependent on the RF power set by the user. A destruction of the lamp could even be produced in the extreme case. A further disadvantage would result in that a part of the RF power would be used by the lamp, whereby a poorer efficiency would be established overall for the equipment. It is also a disadvantage that the lamp cannot be operated with a controlled voltage.